With her pooch in tow, the Gossip Girl star celebrates her 21st b-day on the New York City set of her show. Plus: Ashlee Simpson, Lindsay Lohan, Paris Hilton and more
Credit: Jason LaVeris/FilmMagic
Published: Monday Aug 25, 2008 | 05:50 PM EDT
More from PEOPLE
- Matchmaker Wanted: Find This Harvard MBA a Girlfriend and He'll Pay You $10,000
- Read the Cover Story: Growing Up Kennedy!
Exclusive Family Photos from White House Nanny
- Caitlyn Jenner Shares Patriotic Message on the 4th of July: 'I'm Free to Be Me'
- Inside JFK's Cool Dad Moment – After John Jr.'s White House Jungle Gym Fall
- PEOPLE Exclusive: Kendra Wilkinson Reveals Why She Can't Really Have a Six-Pack Right Now